Technology Field
The present disclosure relates to a memory technique, and particularly relates to a memory management method, a memory storage device and a memory control circuit unit.
Description of Related Art
Digital cameras, mobile phones and MP3 players are quickly developed in recent years, so that consumer demands for storage media have also rapidly increased. Since a rewritable non-volatile memory module (for example, a flash memory) has characteristics of data non-volatility, low power consumption, small volume, and non-mechanical structure, etc., it is adapted to be built in the aforementioned various portable multimedia devices.
Generally, the rewritable non-volatile memory device is configured with normally used physical blocks and spare physical blocks. When data from a host system is to be stored, the data is stored in the spare physical blocks. The spare physical blocks stored with data from the host system are changed to the normally used physical blocks. When data in a certain normally used physical block is deleted by the host system, such physical block is erased and is changed into a spare physical block.
In order to ensure a normal operation of the rewritable non-volatile memory device, a total number of the spare physical blocks in the rewritable non-volatile memory device is generally maintained to be greater than a predetermined number. If the total number of the spare physical blocks is smaller than the predetermined number, a garbage collection procedure is executed. In the garbage collection procedure, valid data scattered in the rewritable non-volatile memory device is collected and centrally stored back in the rewritable non-volatile memory device, so as to release new spare physical blocks.
During the garbage collection procedure, if the host system continuously stores data, the rewritable non-volatile memory device may probably store the data coming from the host system while executing the garbage collection procedure, or may first pause storing the data coming from the host system to accelerate an execution speed of the garbage collection procedure. However, regardless whether the rewritable non-volatile memory device stores the data coming from the host system while executing the garbage collection procedure or first pauses storing the data coming from the host system during the garbage collection procedure, a writing speed of the rewritable non-volatile memory device on the data coming from the host system is in an unpredictable state. For example, at a certain time point, the writing speed of the rewritable non-volatile memory device on the data coming from the host system is probably a full speed, while at a next time point, the rewritable non-volatile memory device may completely pause storing the data coining from the host system due to the garbage collection procedure.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present disclosure. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present disclosure, or that any reference forms a part of the common general knowledge in the art.